Class: MCP::Server

Inherits:
Object
  • Object
show all
Includes:
Instrumentation
Defined in:
lib/mcp/server.rb,
lib/mcp/server/capabilities.rb,
lib/mcp/server/transports/stdio_transport.rb,
lib/mcp/server/transports/streamable_http_transport.rb

Defined Under Namespace

Modules: Transports Classes: Capabilities, MethodAlreadyDefinedError, RequestHandlerError

Constant Summary collapse

DEFAULT_VERSION = 
"0.1.0"
UNSUPPORTED_PROPERTIES_UNTIL_2025_06_18 = 
[:description, :icons].freeze
UNSUPPORTED_PROPERTIES_UNTIL_2025_03_26 = 
[:title, :websiteUrl].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Instrumentation

#add_instrumentation_data, #instrument_call

Constructor Details

#initialize(description: nil, icons: [], name: "model_context_protocol", title: nil, version: DEFAULT_VERSION, website_url: nil, instructions: nil, tools: [], prompts: [], resources: [], resource_templates: [], server_context: nil, configuration: nil, capabilities: nil, transport: nil) ⇒ Server 



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# File 'lib/mcp/server.rb', line 49

def initialize(
  description: nil,
  icons: [],
  name: "model_context_protocol",
  title: nil,
  version: DEFAULT_VERSION,
  website_url: nil,
  instructions: nil,
  tools: [],
  prompts: [],
  resources: [],
  resource_templates: [],
  server_context: nil,
  configuration: nil,
  capabilities: nil,
  transport: nil
)
  @description = description
  @icons = icons
  @name = name
  @title = title
  @version = version
  @website_url = website_url
  @instructions = instructions
  @tool_names = tools.map(&:name_value)
  @tools = tools.to_h { |t| [t.name_value, t] }
  @prompts = prompts.to_h { |p| [p.name_value, p] }
  @resources = resources
  @resource_templates = resource_templates
  @resource_index = index_resources_by_uri(resources)
  @server_context = server_context
  @configuration = MCP.configuration.merge(configuration)
  @client = nil

  validate!

  @capabilities = capabilities || default_capabilities
  @logging_message_notification = nil

  @handlers = {
    Methods::RESOURCES_LIST => method(:list_resources),
    Methods::RESOURCES_READ => method(:read_resource_no_content),
    Methods::RESOURCES_TEMPLATES_LIST => method(:list_resource_templates),
    Methods::TOOLS_LIST => method(:list_tools),
    Methods::TOOLS_CALL => method(:call_tool),
    Methods::PROMPTS_LIST => method(:list_prompts),
    Methods::PROMPTS_GET => method(:get_prompt),
    Methods::INITIALIZE => method(:init),
    Methods::PING => ->(_) { {} },
    Methods::NOTIFICATIONS_INITIALIZED => ->(_) {},
    Methods::LOGGING_SET_LEVEL => method(:configure_logging_level),

    # No op handlers for currently unsupported methods
    Methods::RESOURCES_SUBSCRIBE => ->(_) { {} },
    Methods::RESOURCES_UNSUBSCRIBE => ->(_) { {} },
    Methods::COMPLETION_COMPLETE => ->(_) { { completion: { values: [], hasMore: false } } },
    Methods::ELICITATION_CREATE => ->(_) {},
  }
  @transport = transport
end

Instance Attribute Details

#capabilities ⇒ Object

Returns the value of attribute capabilities.



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# File 'lib/mcp/server.rb', line 47

def capabilities
  @capabilities
end

#configuration ⇒ Object

Returns the value of attribute configuration.



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# File 'lib/mcp/server.rb', line 47

def configuration
  @configuration
end

#description ⇒ Object

Returns the value of attribute description.



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# File 'lib/mcp/server.rb', line 47

def description
  @description
end

#icons ⇒ Object

Returns the value of attribute icons.



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# File 'lib/mcp/server.rb', line 47

def icons
  @icons
end

#instructions ⇒ Object

Returns the value of attribute instructions.



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# File 'lib/mcp/server.rb', line 47

def instructions
  @instructions
end

#logging_message_notification ⇒ Object

Returns the value of attribute logging_message_notification.



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# File 'lib/mcp/server.rb', line 47

def logging_message_notification
  @logging_message_notification
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/mcp/server.rb', line 47

def name
  @name
end

#prompts ⇒ Object

Returns the value of attribute prompts.



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# File 'lib/mcp/server.rb', line 47

def prompts
  @prompts
end

#resources ⇒ Object

Returns the value of attribute resources.



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# File 'lib/mcp/server.rb', line 47

def resources
  @resources
end

#server_context ⇒ Object

Returns the value of attribute server_context.



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# File 'lib/mcp/server.rb', line 47

def server_context
  @server_context
end

#title ⇒ Object

Returns the value of attribute title.



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# File 'lib/mcp/server.rb', line 47

def title
  @title
end

#tools ⇒ Object

Returns the value of attribute tools.



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# File 'lib/mcp/server.rb', line 47

def tools
  @tools
end

#transport ⇒ Object

Returns the value of attribute transport.



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# File 'lib/mcp/server.rb', line 47

def transport
  @transport
end

#version ⇒ Object

Returns the value of attribute version.



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# File 'lib/mcp/server.rb', line 47

def version
  @version
end

#website_url ⇒ Object

Returns the value of attribute website_url.



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# File 'lib/mcp/server.rb', line 47

def website_url
  @website_url
end

Instance Method Details

#define_custom_method(method_name:, &block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 139

def define_custom_method(method_name:, &block)
  if @handlers.key?(method_name)
    raise MethodAlreadyDefinedError, method_name
  end

  @handlers[method_name] = block
end

#define_prompt(name: nil, title: nil, description: nil, arguments: [], &block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 132

def define_prompt(name: nil, title: nil, description: nil, arguments: [], &block)
  prompt = Prompt.define(name: name, title: title, description: description, arguments: arguments, &block)
  @prompts[prompt.name_value] = prompt

  validate!
end

#define_tool(name: nil, title: nil, description: nil, input_schema: nil, annotations: nil, meta: nil, &block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 122

def define_tool(name: nil, title: nil, description: nil, input_schema: nil, annotations: nil, meta: nil, &block)
  tool = Tool.define(name: name, title: title, description: description, input_schema: input_schema, annotations: annotations, meta: meta, &block)
  tool_name = tool.name_value

  @tool_names << tool_name
  @tools[tool_name] = tool

  validate!
end

#handle(request) ⇒ Object 



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# File 'lib/mcp/server.rb', line 110

def handle(request)
  JsonRpcHandler.handle(request) do |method|
    handle_request(request, method)
  end
end

#handle_json(request) ⇒ Object 



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# File 'lib/mcp/server.rb', line 116

def handle_json(request)
  JsonRpcHandler.handle_json(request) do |method|
    handle_request(request, method)
  end
end

#notify_log_message(data:, level:, logger: nil) ⇒ Object 



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# File 'lib/mcp/server.rb', line 171

def notify_log_message(data:, level:, logger: nil)
  return unless @transport
  return unless logging_message_notification&.should_notify?(level)

  params = { "data" => data, "level" => level }
  params["logger"] = logger if logger

  @transport.send_notification(Methods::NOTIFICATIONS_MESSAGE, params)
rescue => e
  report_exception(e, { notification: "log_message" })
end

#notify_prompts_list_changed ⇒ Object 



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# File 'lib/mcp/server.rb', line 155

def notify_prompts_list_changed
  return unless @transport

  @transport.send_notification(Methods::NOTIFICATIONS_PROMPTS_LIST_CHANGED)
rescue => e
  report_exception(e, { notification: "prompts_list_changed" })
end

#notify_resources_list_changed ⇒ Object 



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# File 'lib/mcp/server.rb', line 163

def notify_resources_list_changed
  return unless @transport

  @transport.send_notification(Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED)
rescue => e
  report_exception(e, { notification: "resources_list_changed" })
end

#notify_tools_list_changed ⇒ Object 



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# File 'lib/mcp/server.rb', line 147

def notify_tools_list_changed
  return unless @transport

  @transport.send_notification(Methods::NOTIFICATIONS_TOOLS_LIST_CHANGED)
rescue => e
  report_exception(e, { notification: "tools_list_changed" })
end

#prompts_get_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 207

def prompts_get_handler(&block)
  @handlers[Methods::PROMPTS_GET] = block
end

#prompts_list_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 203

def prompts_list_handler(&block)
  @handlers[Methods::PROMPTS_LIST] = block
end

#resources_list_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 183

def resources_list_handler(&block)
  @handlers[Methods::RESOURCES_LIST] = block
end

#resources_read_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 187

def resources_read_handler(&block)
  @handlers[Methods::RESOURCES_READ] = block
end

#resources_templates_list_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 191

def resources_templates_list_handler(&block)
  @handlers[Methods::RESOURCES_TEMPLATES_LIST] = block
end

#tools_call_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 199

def tools_call_handler(&block)
  @handlers[Methods::TOOLS_CALL] = block
end

#tools_list_handler(&block) ⇒ Object 



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# File 'lib/mcp/server.rb', line 195

def tools_list_handler(&block)
  @handlers[Methods::TOOLS_LIST] = block
end